She appears in the final film in the current series of Lewis (ITV1, Sunday, 8pm) as Esme Ford, making a comeback with band Midnight Addiction.

Which comes as quite a shock to Det Insp Robbie Lewis (Kevin Whately), who once had her poster on his bedroom wall.

Lewis and Det Sgt James Hathaway (Laurence Fox) are called to a church after an unholy row disturbs the Sabbath for a vicar and his congregation, with gunfire drowing out their worship.

Following up the complaint, the two detectives drive to the nearby mansion of rock legend Richie Maguire (David Hayman) to tackle the offenders.

Which is where Lewis comes face to face with the icons of his youth, including lead singer Esme, who was thought to have drowned in Grenada after the group disbanded over 30 years ago.

Joanna says the look of back from the dead Esme was important. “I thought she would be slightly grungy. Once we realised what kind of music the group Midnight Addiction played – practically Black Sabbath – I guessed she was a slightly stoned, fairly wrecked Janis Joplin-type figure.

“I thought Janice looked shocking – stringy, old unwashed hair and sodden clothes – because she only cared about the music. But I thought these lot would have a pretty fabulous look about them. They’d have all worn black leather with eye make-up.

“Esme would have kept up to date with today’s clothes. A lot of people who have been very famous in the rock world tend to have a look when they were at their most famous or when they did best, and hung on to it.”

She adds: “Actors change all the time. We don’t count. You can have well known actors but they never really have a look because they’re always having to change.”

Until she came to film Lewis last autumn, Joanna had never met leading man Kevin. “He’s as sweet as a box of chocolates, just so kind and nice,” she says.

As for his co-star, she recalls: “I must have met Laurence when he was about one. I know his father and mother, and his uncle and others in the family. But I hadn’t met the boy grown up. He leaves a kind of vapour trail.”

Esme’s singing voice on screen is dubbed by Maggie Bell, who some may remember from 1970s’ band Stone The Crows. She also sings No Mean City, the theme music to ITV1’s Taggart.

The rock tracks featured in recording studio scenes are written by Morse and Lewis composer Barrington Pheloung, who also plays lead guitar.

Married for 23 years to classical conductor Stephen Barlow, Joanna admits that music is a big part of her life, although she wouldn’t fall prey to Midnight Addiction.

“I’ve always loved classical music, so apart from the fact that Stephen is 17 light planets ahead of me in everything to do with it, there is no problem. I’m not secretly trying to play my rap records.

When she appeared on Desert Island Discs two years ago, her musical tastes ranged from Wagner to Wham. But Joanna says her choice of Wham’s Last Christmas was a last minute decision forced on her at the BBC recording.

“One of the records I wanted was pulled in the studio. They said, ‘We haven’t got a recording of this.’ So I had to pick on something ridiculous. And as I love that Wham record, because it’s so kind of cheesy, I chose that on the spot.”

Joanna’s most recent TV performance was in the French and Saunders Comic Relief send-up of Mamma Mia! – rated by many to be the highlight of the entire night.

“I do Bafta judging so you get all the films sent to you over Christmas. I had seen Mamma Mia! then, and as soon as I knew Dawn and Jennifer were doing it, my heart soared because they always take on really immense subjects like Titanic of The Silence of the Lambs.

“One of the people we had in the crowd scene, an actress called Mia Soteriou, was in the film and she said it was uncanny being on the set and how beautifully the art department had made the copies of the little bedroom and the café.

“We made enough for practically a feature film. And Philip Glenister as Pierce Brosnan was a thing of beauty. A lot of gorgeousness had to be trimmed.”